In the first 11-and-a-half months of 2010, U.S. President Barack Obama's administration authorized more than twice as many drone strikes, 113, in northwest Pakistan as it did in 2009 -- itself a year in which there were more drone strikes than during George W. Bush's entire time in office.

Given the evident importance of the program to U.S. policy toward Pakistan, it is necessary to ask what we know about the drone strikes, where they happen, and whom they are killing.

Based on updated reports from news organizations with deep and aggressive reporting capabilities in Pakistan (the New York Times, Washington Post, and Wall Street Journal), accounts by major news services and networks (the Associated Press, Reuters, Agence France-Presse, CNN, and the BBC), and reports in the leading English-language newspapers in Pakistan (the Daily Times, Dawn, the Express Tribune, and the News), as well as those from Geo TV, the largest independent Pakistani television network, we have been maintaining a transparent database and interactive map that tracks every reported drone strike since 2004.

Counting drone strikes and fatalities is an art, not a science, as it's not possible to differentiate precisely between militants and nonmilitants because militants live among the population and do not wear uniforms, and because government sources have the incentive to claim that only militants were killed, while militants often assert the opposite.

Still, we've been able to discern some surprising trends. A frequent criticism of the drones program is that the strikes kill too many civilians. In the busiest year of the program, September 2010 was the busiest month, with 22 strikes reported amid news about potential Mumbai-style attacks in Europe, followed by October 2010 with 15 strikes reported and November 2010 with 14. But even as the number of reported strikes has skyrocketed -- with one every three days in 2010, compared with one a week last year and one every 11 days in 2008 -- the percentage of nonmilitants killed by the attacks has plummeted.

Pakistani government officials estimate that more than 700 civilians were killed by the drone strikes last year, but a U.S. government official asserted a year ago that "just over 20" civilians and "more than 400" fighters had been killed in less than two years. U.S. officials continue to claim (anonymously, of course) that only 1 or 2 percent of those killed by the strikes are civilians, and other estimates of civilian deaths range from a high of 98 percent down to 10 percent of the total fatalities.

According to our estimates, the nonmilitant fatality rate since 2004 is approximately 25 percent, and in 2010, the figure has been more like 6 percent -- an improvement that is likely the result of increased numbers of U.S. spies in Pakistan's tribal areas, better targeting, more intelligence cooperation with the Pakistani military, and smaller missiles.

Under the Obama administration, approximately 80 percent of those reported killed by drone strikes have been militants; under the Bush administration, it was closer to 55 percent. The majority of those killed appear to be lower or midlevel militants; of the some 1,260 militants reported killed in the strikes since 2004, only 36, or around 2 percent, have been leaders of al Qaeda, the Taliban, or other militant groups.

Deciphering the true nonmilitant fatality rate from the drone strikes is important as a practical as well as a moral matter. If the true nonmilitant fatality rate were more widely known in Pakistan, the program might be less unpopular there. Those targeted in the strikes, after all, are thought to have carried out or planned attacks not only in Afghanistan and the West, but also in Pakistan, where more than 4,000 people have been killed in militant attacks since the Red Mosque incident in July 2007.

North Waziristan, home to a hornet's nest of militants affiliated with the Haqqani insurgent network, al Qaeda, Tehrik-i-Taliban Pakistan, and other local militants, has been the target of about 90 percent of the reported strikes this year. Given that the region is the source of at least half of the attacks in Afghanistan, this is unsurprising. Before the Pakistani military began a much-anticipated offensive in South Waziristan in October 2009, some 60 percent of the strikes that year took place there; since then, only nine of the 122 reported strikes have occurred in that southernmost tribal area, suggesting a high degree of Pakistani-American coordination. Bolstering this point are reports that the CIA and Pakistan's intelligence service, the ISI, have conducted more than 100 joint operations in the last year and a half, including the arrest of the Taliban's second in command, Mullah Baradar, in early 2010.

Another common refrain from critics of the drones program is that it violates Pakistan's territorial sovereignty, one of the possible reasons the strikes are so unpopular among those who live where the strikes most frequently occur. But despite official public protest, in private Pakistani officials are supportive of the program, and in fact much of the targeting intelligence appears to come from Pakistani sources.

The drone strikes are a tactic, not a strategy. But given Pakistan's negative reaction both to a Special Forces raid in South Waziristan in early September 2008 and to NATO helicopter strikes in Kurram in late September 2010, plus the Pakistani military's unwillingness to mount major offensives in North Waziristan, it's not clear what additional options the United States has. Militantscontinue to seek to attack the West from the tribal areas, despite the drone program's escalation. U.S. officials are reportedly even seeking the expansion of the program into Quetta, where the leadership of the Taliban is believed to be based. So despite the controversies about civilians, sovereignty, and strategy, the strikes are still, as CIA chief Leon Panetta commented in May 2009, "the only game in town." For that reason, it's worthwhile for everyone to understand exactly what the rules of the game are and continue to be.